This invention relates to a bimetal circuit breaker switch assembly which is of the type that has two parallel, side-by-side arranged snap switches associated with two circuits independent from one another, a plate-like bimetal element which is, at its arcuately moving free end, operatively connected with the actuating ends of the snap switches, and a desired value setter arranged approximately at right angles to the length dimension of the snap switches. The desired value setter may be advanced or withdrawn by virtue of a threaded engagement and is in contact with a cantilevered transmitting element positioned parallel to the snap switches. To a freely swinging end of the transmitting element there is secured a snap spring which is biased and which is stamped out of the plate material forming the snap contacts. The two snap switches as well as the transmitting element are accommodated in a common insulator housing.
A circuit breaker of the above-outlined type is disclosed, for example, in German Gebrauchsmuster (Utility Model) No. 1,970,622.
Bimetal switches of the above type which have first and second independent snap switches are used with preference in heating devices which have two separate heating coils. In these devices, for a first heat-up range the main current contacts of both switches are closed, while in an upper temperature range the terminal heat-up is effected only by one of the two circuits. Stated differently, the main current contacts of the second switch have to be open in such a terminal heat-up phase.
If the temperature exceeds a preset maximum value, the main current contacts of the second snap switch also open. If the temperature slightly drops below the upper tripping point, a room temperature regulation is effected exclusively by a closing and opening of the second snap switch.
If the temperature falls below the tripping point of the first snap switch, the contacts of both snap switches should close in response, to ensure that a rapid heat-up of the room to the desired temperature will again follow. Known switches which in most cases are situated in the immediate vicinity of the heat sources, do not perform in this respect with satisfactory results. At the moment of closing the second snap switch as the temperature drops below the upper maximum tripping temperature, the heat radiated from the second heating coil, and affecting the bimetal is so high that a regulation is, disadvantageously, effected solely with the second heating coil since only the second snap switch is switched on and off. Stated differently, the first heating coil (in which the current flow is controlled by the first snap switch) is not energized at all, resulting in a slow cooling of the environmental temperature of the heating element and thus the regulating system does not respond within a certain comfort range.